Thank you for the reply. One of the ideas I came up with, used a spring to make sure the gear dropped down, and a cable to pull it back up. I have also looked at micro air cylinders, which could be used along with a sequencing valve to do the same. My problem is how to mount the gear so it looks scale, and is able to drop down then rotate as it pivots back. Do you have any sketches you could share?
Thanks